Four port circulators

In a quasi-optical Faraday rotator, it is arranged that the single pass rotation provided by the ferrite is 45°, and therefore a signal which passes through the rotator twice will be orthogonally polarised with respect to the original input signal. These transmitted and received signals are then easily separated using a polariser grid. The diagram below shows the construction of a four port quasi-optical circulator using two polariser grids and a quasi-optical Faraday rotator.



By increasing our understanding of the properties of ferrite materials at millimetre wave frequencies via experimental characterisation work, we have improved the insertion loss and isolation performances of the quasi-optical Faraday rotators that we construct. As part of this work we have also developed characterisation systems for the evaluation of dielectric materials. This data enables us to choose the most suitable available dielectric materials for use in the construction of quasi-optical Faraday rotators and other quasi-optical system components. We also sell faraday rotators so please contact us if you require further information.